Enhancement of plant growth

ABSTRACT

Treatment with N-(2-phenylethyl)succinamic acid or its salts protects against inhibition of growth by a neonicotinoid compound applied as a seed treatment or applied directly on or near the root zone of the seedling.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.12/257,475, filed on Oct. 24 2008, which claims the benefit of U.S.Provisional Patent Application Ser. No. 61/000,366, filed on Oct. 25,2007, the contents of which are incorporated herein by reference intheir entirety.

FIELD OF THE INVENTION

The present invention is directed to improving plant growth andconsequently yield using N-(2-phenylethyl)succinamic acid (PESA) or itssalt, in the presence of a neonicotinoid compound. This is accomplishedusing a combination treatment of PESA or its salt and a neonicotinoidcompound applied as a seed treatment or applied directly to or near theroot zone of a seedling or growing plant.

BACKGROUND OF THE INVENTION

Seeds are commonly treated with pesticides to control insects,nematodes, and disease organisms such as fungi and bacteria.Neonicotinoid compounds are commonly active ingredients of insecticidesused for treating seeds. Among the commercially available neonicotinoidcompounds are clothianidin (tradename Poncho®), imidacloprid (tradenameGauche®), thiamethoxam (tradename Cruiser®), and dinotefuran (tradenameSafari®). N-(2-phenylethyl)succinamic acid is root growth promoter(Soejima, H., et al., Plant Cell Physiol., 2000, 41, p. 197; Itagaki,M., et al., 6th Symposium of the International Society of Root Research,2001, C1-8; Itagaki, M., et al., Plant Soil, 2003, 255, p. 67-75).Effects of combinations of neonicotinoid compounds and PESA or its saltson plant growth have not been previously examined.

SUMMARY OF THE INVENTION

The present invention is directed to improving plant growth andconsequently yield using PESA or its salt in the presence of aneonicotinoid compound. This is accomplished by using a combinationtreatment of PESA or its salt and at least one neonicotinoid compoundapplied as a seed treatment or applied directly to or the root zone of aseedling or growing plant. Alternatively, the combination treatment ofthe present invention may be applied to the shoots or leaves of theplant. This invention permits the use of higher rates of neonicotinoidcompounds. The combination treatment can be performed by applying acomposition comprising PESA or its salt and a neonicotinoid compound aswell as by applying PESA or its salt and a neonicotinoid compoundseparately.

DETAILED DESCRIPTION OF THE INVENTION

Seed treatments are used on a large variety of crops to control pests.Seed treatments are commonly used to ensure uniform stand establishmentby protecting against diseases and insects. Systemic seed treatments mayprovide an alternative to foliar sprays of fungicides or insecticidesfor certain early season diseases and insects.

Conventional means of coating may be used for carrying out the coatingof the seed treatment formulation. Various coating machines and methodsare available to one skilled in the art. Well known techniques includethe use of drum coaters and fluidized bed techniques. Other methods,such as spouted beds, may also be useful.

Film-forming compositions for enveloping seeds are well known in theart, and a film overcoat can be optionally applied to the coated seedsof the present invention. The film overcoat protects the coating layersand may allow easy identification of the treated seeds. In general,additives are dissolved or dispersed in a liquid adhesive, usually apolymer, into which or with which seeds are dipped or sprayed beforedrying. Alternatively, a powder adhesive can be used. Various materialsare suitable for overcoats including but not limited to, methylcellulose, hydroxypropylmethylcellulose, dextrin, gums, waxes, vegetableor paraffin oils; water soluble or water disperse polysaccharides andtheir derivatives, such as alginates, starch, and cellulose; andsynthetic polymers such as polyethylene oxide, polyvinyl alcohol,polyvinylpyrrolidone, and their copolymers, related polymers, andmixtures of these.

Further materials may be added to the overcoat optionally includingplasticizers, colorants, brighteners and surface active agents, such asdispersants, emulsifiers and flow agents, including, for example,calcium stearate, talc and vermiculite. Additionally, pesticides, suchas fungicides, may be added to the film coat. However, it has beenobserved that fungicides initially added to the seed provide betterresults than when added with the overcoat. Fluidized bed and drum filmcoating techniques described above can also be employed for filmcoating.

Many seed treatment materials are also available for on-farm use whereinliquid or dry formulations are applied to seed as it passes through anauger from the transport bin or truck to planter boxes. Theseformulations offer a convenient way to apply seed treatment onto bulkseed right before planting. Conventional dry treatments generally areformulated with talc or graphite that adhere the treatment chemical tothe seed. Conventional liquid hopper-box treatments generally are madeavailable as fast-drying formulations. In any case, good seed coverageis required for maximum benefit from any seed treatment formulation.

For purposes of this application, PESA is defined asN-(2-phenylethyl)succinamic acid which can be prepared by the methoddescribed in WO 99/45774. Clothianidin is defined as(E)-1-(2-chloro-1,3-thiazol-5-ylmethyl)-3-methyl-2-nitroguanidine,imidacloprid is defined as(EZ)-1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine,thiamethoxam is defined as(EZ)-3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine,and dinotefuran is defined as(EZ)-(RS)-1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine.

Suitable neonicotinoid compounds include but are not limited to,clothianidin, imidacloprid, thiamethoxam, dinotefuran, acetamiprid,nytenpyram and thiacloprid.

Suitable salts of PESA include, but are not limited to the calcium,magnesium, potassium, sodium or ammonium salts. The presently preferredsalt is the sodium salt. Ammonium salts include the salts formed byneutralization of the acid by ammonia itself or by amines bearing one,two or three lower alkyl groups and/or hydroxy-lower alkyl groups,wherein lower alkyl is defined as consisting of one to four carbon atomsarranged in a straight or branched chain. Suitable amines include, butare not limited to trimethylamine, isopropylamine, ethanolamine,dimethylethanolamine, diethanolamine or triethanolamine.

The phrase “the root zone of a seedling or plant” means a zone where theroot is spread underground, generally a zone from 1 to 100 cm of radiusfrom the center of the seedling or growing plant.

Preparation of PESA Salt

Salts of PESA were produced by stirring the free acid in water andadding an equimolar amount of an appropriate base to the solution. Inthe case of the PESA sodium salt, sodium hydroxide is used. This methodallows for the production of salt solutions ranging in concentrationfrom 0.01% to at least 40%.

Use of PESA or PESA Salts

The concentration of PESA or PESA salt is preferably in the range of0.021 to 20.1 percent by volume of the composition, and theconcentration of the neonicotinoid compound is preferably in the rangeof 0.3 to 30.0 percent by weight of the composition.

The weight ratio of the PESA or PESA salt to the neonicotinoid compoundin the compositions of the present invention is 1:40 to 1:1, preferably1:20 to 1:2, and most preferably 1:10 to 1:3.

Aqueous compositions to be utilized in the present invention generallycontain from at least about 2% to about 10% by weight of asurface-active agent. In one embodiment, the aqueous compositionscontain from about 3% to about 7% by weight of a surface-active agent.

The aqueous composition generally also comprises an anionic surfactant.In general, the anionic surfactant may be any known anionic surfactantin the art. Suitable anionic surfactants are in general oligomers andpolymers, as well as polycondensates, which contain a sufficient numberof anionic groups to ensure their water-solubility. Suitable anionicsurfactants include alcohol sulfates, alcohol ether sulfates, alkylarylether sulfates, alkylaryl sulfonates such as alkylbenzene sulfonates andalkylnaphthalene sulfonates and salts thereof, alkyl sulfonates, mono-or di-phosphate esters of polyalkoxylated alkyl alcohols oralkylphenols, mono- or di-sulfosuccinate esters of C₁₂-C₁₅ alkanols orpolyalkoxylated C₁₂-C₁₅ alkanols, alcohol ether carboxylates, phenolicether carboxylates, polybasic acid esters of ethoxylated polyoxyalkyleneglycols consisting of oxybutylene or the residue of tetrahydrofuran,sulfoalkylamides and salts thereof such as N-methyl-N-oleoyltaurate Nasalt, polyoxyalkylene alkylphenol carboxylates, polyoxyalkylene alcoholcarboxylates alkyl polyglycoside/alkenyl succinic anhydride condensationproducts, alkyl ester sulfates, napthalene sulfonates, naphthaleneformaldehyde condensates, alkyl sulfonamides, sulfonated aliphaticpolyesters, sulfate esters of styrylphenyl alkoxylates, and sulfonateesters of styrylphenyl alkoxylates and their corresponding sodium,potassium, calcium, magnesium, zinc, ammonium, alkylammonium,diethanolammonium, or triethanolammonium salts, salts of ligninsulfonicacid such as the sodium, potassium, mamesium, calcium or ammonium salt,polyarylphenol polyalkoxyether sulfates and polyarylphenolpolyalkoxyether phosphates, and sulfated alkyl phenol ethoxylates andphosphated alkyl phenol ethoxylates.

The aqueous composition generally also includes at least one polymerselected from water-soluble and water-dispersible film-forming polymers.Suitable polymers have an average molecular weight of at least about1,000 up to about 100,000; more specifically at least about 5,000, up toabout 100,000. The aqueous compositions generally contain from about0.01% to about 10%, preferably about 0.05 to about 8%, more preferablyabout 0.1% to about 5%, especially about 0.5% to about 4% by weight ofthe composition of polymer. In a specific embodiment, the compositionscontain from about 1.0% up to about 4% by weight of a film-formingpolymer. In another embodiment, the compositions contain about 0.05 to1% by weight of the film-forming polymer.

Suitable polymers include alkyleneoxide random and block copolymers suchas ethylene oxide-propylene oxide block copolymers (EO/PO blockcopolymers), including both EO-PO-EO and PO-EO-PO block copolymers;ethylene oxide-butylene oxide random and block copolymers, C₂₋₆ alkyladducts of ethylene oxide-propylene oxide random and block copolymers,C₂₋₆ alkyl adducts of ethylene oxide-butylene oxide random and blockcopolymers, polyoxyethylene-polyoxypropylene monoalkylethers, such asmethyl ether, ethyl ether, propyl ether, butyl ether or mixturesthereof; vinylacetate/vinylpyrrolidone copolymers; alkylatedvinylpyrrolidone copolymers; polyvinylpyrrolidone; andpolyalkyleneglycol, including the polypropylene glycols and polyethyleneglycols.

The aqueous composition generally also comprises, from at least about 3to about 25% of at least one antifreeze agent. In one embodiment, theamount of an antifreeze agent is from about 6% to about 20% by weight.

Specific examples of suitable antifreezes include ethylene glycol,1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol,1,3-butanediol, 1,4-butanediol, 1,4-pentanediol,3-methyl-1,5-pentanediol, 2,3-dimethyl-2,3-butanediol, trimethylolpropane, mannitol, sorbitol, glycerol, pentaerythritol,1,4-cyclohexanedimethanol, xylenol, bisphenols such as bisphenol A orthe like. In addition, ether alcohols such as diethylene glycol,triethylene glycol, tetraethylene glycol, polyoxyethylene orpolyoxypropylene glycols of molecular weight up to about 4000,diethylene glycol monomethylether, diethylene glycol monoethylether, triethylene glycol monomethylether, butoxyethanol, butylene glycolmonobutylether, dipentaerythritol, tripentaerythritol,tetrapentaerythritol, diglycerol, triglycerol, tetraglycerol,pentaglycerol, hexaglycerol, heptaglycerol, octaglycerol and the like.

Additionally, a coloring agent, such as a dye or pigment, may beincluded in the seed coating so that an observer can immediatelydetermine that the seeds are treated. The dye is also useful to indicateto the user the degree of uniformity of the coating applied.

The formulations of the present invention contain sufficient water tobring the total weight to 100%.

The formulations of the present invention are applied to seeds or to theroot zone at rates of 1 to 2000 grams active ingredients/acre andpreferably 5 to 200 grams active ingredients/acre.

A formulation comprising PESA or its salt as an active ingredient andanother formulation comprising a neonicotinoid compound as an activeingredient can be applied to seeds or to or the root zone separately.The total application rate of the formulations is 1 to 2000 grams activeingredients/acre and preferably 5 to 200 grams active ingredients/acre.The weight ratio of the PESA or PESA salt to the neonicotinoid compoundapplied is 1:40 to 1:1, preferably 1:20 to 1:2, and most preferably 1:10to 1:3.

Especially suitable target crops comprise cereals (such as wheat,barley, rye, oats, rice), maize, sugar beet, cotton, millet, sorghum,sunflower, bean, peas, oil plants (such as canola, rape, and soybean),potato, tomato, eggplant, pepper, and other vegetables (such ascucurbits and cole crops) and spices, as well as woody perennials,ornamental shrubs, fruit trees, grapevines, fruits (such as strawberriesand blueberries),turf, grass, pastures and flowers.

Suitable target crops also include non-transgenic or transgenic cropplants of the foregoing crops. The transgenic crop plants usefulaccording to the invention are plants, or propagation material thereofwhich are transformed by recombinant DNA technology in order toincorporate certain desired traits such as, but not limited to,synthesis of selectively acting toxins from toxin-producinginvertebrates, especially of the phylum Arthropoda; from Bacillusthuringiensis strains; from plants, such as lectins; or in thealternative, capable of expressing a herbicidal or fungicidalresistance.

The compositions are particularly suited for applications on plantpropagation material. The latter term embraces seeds of all kinds (e.g.fruit, tubers, or grains), cuttings, cut shoots and the like. Thepreferred field of application is the treatment of all kinds of seeds asspecified in the target crops above, and in particular, the seedtreatment of canola, maize, cereals, soybeans and other legumes andcrops.

Procedure for Treating Samples of Seed in the Laboratory

Seed was sieved with a screen of hole size appropriate to remove brokenseeds and small trash. Cracked or otherwise damaged seeds were removed.The seed was well mixed, and 50 g samples were weighed into smallplastic trays. Seed treatment slurries were made by adding measuredamounts of the active ingredients to sufficient water to bring them upto a standard volume, typically 2 ml. A fungicide (Maxim XL; SyngentaAgricultural Products, Greensboro, N.C.), a polymeric binder (CF-Clear;Becker-Underwood, Ames, Iowa), and a colorant (Color Coat Red;Becker-Underwood, Ames, Iowa) were also included in the slurry at labelrates. A small aliquot of this slurry was applied to the seed using theHege 11 coater (Wintersteiger, Salt Lake City, Utah) with a six-inchbowl. The slurry was deposited drop-wise on the spinning disk atomizerusing a syringe.

Pouch Assay

Seeds were placed in germination pouches consisting of germination paperhydrated with sterile water that was an insert in a gas-permeable 16×14cm plastic pouch (CYG Pouch; Mega International, St. Paul, Minn.). Inthese examples, in pouch solution evaluation, clothianidin and PESAsodium salt were added to the sterile water in the pouch. Alternatively,imidacloprid or dinotefuran and PESA sodium salt were added to thesterile water in the pouch. The pouches were arranged in a completelyrandomized block design in growth racks and placed in 19-literpolycarbonate food storage containers (Rubbermaid Commercial Products,Winchester, Va.). The sealed containers were held in an upright growthcabinet maintained at 25 C with a 12 hour light: 12 hour darkphotoperiod. After 6 days, the containers were removed from the growthcabinet, and the lengths of the roots and shoot were measured.

Field Studies

For the field studies, the seed was treated with a seed treatmentformulation containing clothianidin. The rate of clothianidin wasdependent on the crop species. The seed treatment formulations wereamended with the appropriate concentrations of either PESA or the sodiumsalt of PESA.

Crops were planted and grown under standard agricultural practices, andevaluated at the times indicated.

The following examples are intended to illustrate the present inventionand to teach one of ordinary skill in the art how to make and use theinvention. They are not intended to he limiting in any way.

EXAMPLES Example 1 Preparation Example

The following representative formulations in which all percentages areweight percentages may be prepared.

Formulation A (in-bottle formulation of PESA salt and neonicotinoid):

-   -   PESA Sodium Salt: 5%    -   Clothianidin: 30%    -   Tween 20: 5%    -   N-methyl pyrrolidone 20%    -   Polyvinyl acetate: 2%    -   Potassium Sorbate: 1%    -   Water: 37%.

Clothianidin may be mixed with N-methyl pyrrolidone and Tween 2U at roomtemperature to produce a concentrate. Separately, the sodium salt ofPESA may be mixed with polyvinyl acetate and potassium sorbate in waterto produce an aqueous mixture. While stirring the aqueous mixture, theclothianidin-containing concentrate may be added. This will produce aformulation that may be used for the treatment of seeds, plants, orapplied to the root zone of seedlings or plants.

Formulation B (in-bottle formulation of PESA and neonicotinoid):

-   -   Milled PESA: 5%    -   Clothianidin: 30%    -   Tween 20: 5%    -   N-methyl pyrrolidone 16%    -   Polyvinyl acetate: 2%    -   Potassium Sorbate: 1%    -   Lignin Sulfate: 1%    -   Water: 40%.

Clothianidin may be mixed with N-methyl pyrrolidone and. Tween 20 atroom temperature to produce a concentrate. Separately, PESA may be mixedwith lignin sulfate, Tween 20 and water and milled in a wet millingmachine for 1-2 hours in order to reduce particle size. The milled PESAmay be mixed with polyvinyl acetate and potassium sorbate to produce anaqueous mixture. While stirring the aqueous mixture, theclothianidin-containing concentrate may be added. This will produce aformulation that may be used for the treatment of seeds, plants, orapplied to the root zone of seedlings or plants.

Formulation C (separate bottle formulations of PESA salt andneonicotinoid):

-   -   Bottle 1:    -   PESA Sodium Salt: 10%    -   Tween 20: 10%    -   Polyvinyl acetate: 2%    -   Potassium Sorbate: 1%    -   Water: 77%.

The sodium salt of PESA may be mixed with polyvinyl acetate, Tween 20and potassium sorbate in water to produce an aqueous mixture.

-   -   Bottle 2:    -   Clothianidin 60%    -   Tween 20: 5%    -   N-methyl pyrrolidone: 35%.

Clothianidin may be mixed with N-methyl pyrrolidone and Tween 20 at roomtemperature to produce a concentrate.

While stirring the aqueous mixture in bottle 1, theclothianidin-containing concentrate in bottle 2 may be added. This willproduce a formulation that may be used for the treatment of seeds,plants, or applied to the root zone of seedlings or plants.

Formulation D (separate bottle formulations of PESA and neonicotinoid):

-   -   Bottle 1:    -   Milled PESA: 10%    -   Tween 20: 10%    -   Lignin Sulfate 1%    -   Polyvinyl acetate: 2%    -   Potassium Sorbate: 1%    -   Water: 76%.

PESA may be mixed with lignin sulfate, Tween 20 and water and milled ina wet milling machine for 1-2 hours in order to reduce particle size.The milled PESA may be mixed with polyvinyl acetate and potassiumsorbate to produce an aqueous mixture.

-   -   Bottle 2:    -   Clothianidin 60%    -   Tween 20: 5%    -   N-methyl pyrrolidone: 35%.

Clothianidin may be mixed with N-methyl pyrrolidone and Tween 20 at roomtemperature to produce a concentrate.

While stirring the aqueous mixture in bottle 1, theclothianidin-containing concentrate in bottle 2 may be added. This willproduce a formulation that may be used for the treatment of seeds,plants, or applied to the root zone of seedlings or plants.

Example 2

Seed treatment with clothianidin alone with 182 or 364 g/100 pounds ofseed reduced cotton root length (Table 1). A seed treatment combinationof clothianidin with PESA salt increased the root length of cotton. Forcotton treated with the lower rate of 10 grams PESA salt/100 pounds ofseed combined with 182 or 364 grams clothianidin/100 pounds of seed,root length was greater than control, PESA salt alone, or clothianidinalone at the respective rates. For cotton treated with the higher rateof 25 grams PESA salt/100 pounds of seed combined with 182 or 364 gramsclothianidin/100 pounds of seed, root length was greater than control,or clothianidin alone at the respective rates.

This indicates that PESA salt safened cotton againstclothianidin-induced root growth inhibition.

TABLE 1 Effect of PESA salt and clothianidin seed treatments on rootlength (cm) of cotton. PESA salt (grams/100 Clothianidin (grams/100pounds of seed) pounds of seed) 0 182 364  0  9.6  7.8 7.9 10  8.8  9.09.1 25 10.6 10.1 9.8 n = 7 replicate pouches of 3 plants/pouch pertreatment.

Treatment with clothianidin alone, PESA salt, and combinations ofclothianidin with PESA salt increased cotton shoot length (Table 2).

TABLE 2 Effect of PESA salt and clothianidin seed treatments on shootlength (cm) of cotton. PESA salt Clothianidin (grams/100 pounds(grams/100 pounds of seed) of seed) 0 182 364  0 3.7 4.1 4.2 10 4.3 4.34.2 25 4.3 4.0 4.2 n = 7 replicate pouches of 3 plants/pouch pertreatment.

Example 3

In continuous exposure pouch studies, treatment with clothianidin alonedecreased the length of the root (Table 3). PESA salt increased rootlength in a dose-dependent manner. The combination of clothianidin and100 mg/liter PESA salt increased root length compared to the untreatedcontrol.

This indicates that PESA salt safened cotton againstclothianidin-induced root growth inhibition.

TABLE 3 Effect of PESA salt and clothianidin on root length (cm) ofcotton. Clothianidin (mg/liter) PESA salt (mg/liter) 0 1000  0 11.4  8.9 10 14.2 10.0  30 15.3 10.4 100 16.2 12.5 n = 8 replicate pouches of 3seedlings/pouch per treatment.

In continuous exposure pouch studies, cotton shoot length was notaffected by clothianidin alone (Table 4). Shoot length of the treatmentwith the 300 mg/liter (the highest rate) of PESA salt alone was reduced,but was not affected by the combination of clothianidin with 300mg/liter PESA salt.

TABLE 4 Effect of PESA salt and clothianidin on shoot length (cm) ofcotton Clothianidin (mg/liter) PESA salt (mg/liter) 0 1000  0 6.1 6.1 10 6.3 6.2  30 6.1 6.0 100 6.0 6.1 300 5.4 5.8 n = 8 replicate pouchesof 3 seedlings/pouch per treatment.

Example 4

In a continuous exposure pouch study, treatment with imidacloprid (1000mg/liter) alone decreased root length (Table 5). Root lengths ofcombination treatments of imidacloprid with PESA salt were greater thanroot length of the imidacloprid alone treatment. Root lengths of thecontrol and combination treatment of imidacloprid with 100 mg/liter PESAsalt were similar.

This indicates that PESA salt safened cotton againstimidacloprid-induced root growth inhibition.

TABLE 5 Effect of PESA salt and imidacloprid on root length (cm) ofcotton Imidacloprid mg/liter) PESA salt (mg/liter) 0 1000  0 13.3  7.7 10 14.6  9.4  30 16.9 12.1 100 16.5 13.6 300 11.9 12.0 n = 8 replicatepouches of 3 seedlings/pouch per treatment.

Cotton shoot length was not affected by imidacloprid alone (Table 6).Shoot length of the combination treatment of imidacloprid with highestrate (300 mg/liter) of PESA salt was reduced.

TABLE 6 Effect of PESA salt and imidacloprid on shoot length (cm) ofcotton Imidacloprid (mg/liter) PESA salt (mg/liter) 0 1000  0 6.2 6.0 10 6.2 5.8  30 6.0 5.8 100 6.0 5.8 300 5.7 5.4 n = 8 replicate pouchesof 3 seedlings/pouch per treatment.

Example 5

In a continuous exposure pouch study with PESA salt solutions, seedtreatment with imidacloprid alone decreased the root length in adose-dependent manner (Table 7). Inclusion of PESA salt (50 mg/liter) inthe pouch increased the root length of the imidacloprid-treated seed.Root lengths of the control and combination treatment of 200 gramsimidacloprid/100 pounds of seed with 50 mg/liter PESA salt were similar.

This indicates that PESA salt safened, rice against imidacloprid-inducedroot growth inhibition.

TABLE 7 Effect of PESA salt and imidacloprid on root length (cm) of riceImidacloprid (grams/100 PESA salt (mg/liter) pounds of seed) 0 50  010.7 12.0 200  9.6 10.5 400  8.9  9.8 800  8.3  8.7 n = 8 replicatepouches of 3 seedlings/pouch per treatment.

Rice shoot lengths for imidacloprid alone and in combination with PESAsalt were similar (Table 8).

TABLE 8 Effect of PESA salt and imidacioprid on shoot length (cm) ofrice Imidacloprid (grams/100 PESA salt (mg/liter) pounds of seed) 0 50 0 3.3 3.6 200 3.6 3.7 400 3.3 3.1 800 3.6 2.9 n = 8 replicate pouchesof 3 seedlings/pouch per treatment.

Example 6

The sodium salt of PESA was prepared as described above, and was used inseed treatment either alone or in the presence of clothianidin. Soybeanseed was treated with 0 or 50 grams of clothianidin/100 kg (220 pound)of seed and with 0, 22, 55, or 137.5 grams PESA salt/100 kg seed.Clothianidin alone reduced plant height as compared to the control.Plant height of seeds treated with clothianidin and PESA salt at 22 and55 grams/100 kg was greater than that of the clothianidin alone (Table9).

This indicates that PESA salt safened soybean againstclothianidin-induced root growth inhibition.

TABLE 9 Effect of PESA salt and clothianidin seed treatment on averageplant height (inches) of soybean at 66 days after planting nearIndianapolis, IN, USA Clothianidin (g/100 kg Sodium salt of PESA (g/seed) 100 kg/seed) Plant Height (inches) 0 0 23.8 50 0 21.6 50 22 24.850 55 24.1 50 137.5 22.1 0 22 23.8 0 55 23.5 0 137.5 23.2

Example 7

The sodium salt of PESA was prepared as described above, and was used inseed treatment either alone or in the presence of clothianidin. Sorghumseed was treated with 0 or 200 grams of clothianidin/100 kg (220 pound)of seed and with 0, 22, 55, or 137.5 grams PESA salt/100 kg seed.Clothianidin alone reduced root dry weight as compared to the control.Root dry weight from seeds treated with clothianidin and PESA salt at 22and 55 grams/100 kg had greater root dry weight than the clothianidinalone (Table 10).

This indicates that PESA salt safened sorghum againstclothianidin-induced root growth inhibition.

TABLE 10 Effect of PESA salt and clothianidin seed treatment on root dryweight of a sample of 10 sorghum plants at 73 days after planting nearIndianapolis, IN, USA Clothianidin (g/100 kg Sodium salt of PESA seed)(g/l00 kg/seed) Root Dry Weight (grams) 0 0 148.5 200 0 108.7 200 22124.1 200 55 143.4 200 137.5 136.0 0 22 183.5 0 55 146.5 0 137.5 141.6

Example 8

The sodium salt of PESA was prepared as described above, and was used inseed treatment either alone or in the presence of clothianidin. Canola(Brassica napus) seed was treated with 0 or 400 grams ofclothianidin/100 kg (220 pound) of seed and with 0, 22, 55, or 137.5grams PESA salt/100 kg seed. Clothianidin alone reduced plant vigor ascompared to the control. Plant vigor from seeds treated withclothianidin and PESA salt at all rates had greater plant vigor than theclothianidin alone (Table 11).

This indicates that PESA salt safened canola againstclothianidin-induced vigor reduction.

TABLE 11 Effect of PESA salt and clothianidin seed treatment on vigorrating (1 = low and 5 = high) of canola plants at 19 days after plantingnear Portage la Prairie, Manitoba, Canada. Clothianidin Sodium salt ofPESA (g/100 kg seed) (g/100 kg/seed) Vigor (1-5) 0 0 3.8 400 0 2.5 40022 3 400 55 3 400 137.5 3 0 22 3.8 0 55 4 0 137.5 4

Example 9

The PESA or the sodium salt of PESA was prepared as described above, andwas used in seed treatment either alone or in the presence ofclothianidin. Maize (Zea mays) seed was treated with 0 or 0.25milligrams of clothianidin/seed and with 0, 22, 55, or 137.5 grams PESAsalt/100 kg seed. Clothianidin alone reduced plant vigor as compared tothe control. Plant vigor from seeds treated with clothianidin and PESAor the sodium salt of PESA had greater plant vigor than the clothianidinalone (Table 12).

This indicates that PESA or the sodium salt of PESA safened maizeagainst clothianidin-induced vigor reduction.

TABLE 12 Effect of PESA or the sodium salt of PESA and clothianidin seedtreatment on vigor rating of maize plants at 27 days after planting nearWhitewater, Wisconsin. Clothianidin (mg/seed) PESA (g/100 kg/seed) Vigor(1-5) 0  0 3.6 0.25  0 3.1 0.25   22 (Sodium salt) 3.6 0.25   55 (Sodiumsalt) 3.6 0.25 137.5 (Sodium salt) 3.2 0.25 55 3.6 0   22 (Sodium salt)3.8 0   55 (Sodium salt) 3.5 0 137.5 (Sodium salt) 3.4

1. A composition for enhancing plant growth comprisingN-(2-phenylethyl)succinamic acid (PESA) or its salt and at least oneneonicotinoid compound wherein the ratio of PESA to neonicotinoid isfrom 1:0.4 to 1:100.
 2. The composition of claim 1 wherein theN-(2-phenylethyl)succinamic salt is the sodium salt.
 3. The compositionof claim 1 wherein the ratio of PESA to neonicotinoid is from 1:0.4 to1:3.3.
 4. The composition of claim 3 wherein the neonicotinoid compoundis clothianidin.
 5. The composition of claim 3 wherein the neonicotinoidcompound is imidacloprid.
 6. The composition of claim 1 wherein theratio of PESA to neonicotinoid is from 1:1 to 1:100.
 7. The compositionof claim 6 wherein the neonicotinoid compound is thiamethoxam.
 8. Thecomposition of claim 6 wherein the neonicotinoid compound isdinotefuran.
 9. The composition of claim 1 wherein the ratio of PESA toneonicotinoid is 1:1.
 10. The composition of claim 2 wherein theconcentration of the N-(2-phenylethyl)succinamic acid salt is from 0.021percent to 20.1 percent by volume of the composition.
 11. Thecomposition of claim 1 wherein the concentration of the neonicotinoidcompound is from 0.3 percent to 30 percent by weight of the composition.12. A method of enhancing the growth of plants by applying an effectiveamount of N-(2-phenylethyl)succinamic acid or its salt and aneonicotinoid compound to seeds or the root zone of seedlings or plantswherein the ratio of PESA to neonicotinoid is from 1:0.4 to 1:100. 13.The method of claim 12 wherein the ratio of PESA to neonicotinoid isfrom 1:0.4 to 1:3.3.
 14. The method of claim 12 wherein the ratio ofPESA to neonicotinoid is 1:1.
 15. The method of claim 12 wherein theN-(2-phenylethyl)succinamic acid or its salt and the neonicotinoidcompound are applied to seeds wherein the ratio of PESA to neonicotinoidis from 1:0.4 to 1:100.
 16. A method of enhancing the growth of plantsby applying an effective amount of the composition of claim 1 to seedsor the root zone of seedlings or plants.
 17. The composition of claim 16wherein the ratio of PESA to neonicotinoid is from 1:0.4 to 1:3.3. 18.The composition of claim 16 wherein the ratio of PESA to neonicotinoidis 1:1.
 19. The method of claim 16 wherein the composition is applied toseeds.
 20. A method for safening plants by applying an effective amountof N-(2-phenylethyl)succinamic acid or its salt against a neonicotinoidcompound-induced growth inhibition to seeds or the root zones ofseedlings or plants.
 21. The method of claim 20 wherein the ratio ofPESA to neonicotinoid is from 1:0.4 to 1:3.3.
 22. The method of claim 20wherein the ratio of PESA to neonicotinoid is 1:1.